The technical field of the present invention relates to practice munitions and projectiles, and in particular, to projectiles that disintegrate as they leave the barrel of a weapon.
In the field of practice munitions, a distinction is generally drawn between those designed to reproduce the actual ballistics of a live projectile, but over a short distance, (i.e., practice projectiles that follow at least a partial ballistic trajectory) and those designed only to reproduce the environment specific to firing (noise, recoil, smoke, etc.).
The first type of practice munitions is illustrated by patents FR 2509457 and DE 734429, both of which describe a projectile having a body formed by assembling several segments. This type of practice projectile is designed to reproduce the actual ballistics of a live projectile over a predetermined distance. Therefore, this projectile includes structure to ensure that the various segments are held together over a portion of the trajectory. Use of this type of practice projectile requires installing a firing safety fixture. In addition, this type of practice projectile can be used only to reproduce the firing environment.
For munitions that are designed to reproduce a firing environment, so-called blank munitions having no projectile are known. In other words, the portions of these munitions that are fired fall to the ground at a short distance from the weapon and thus do not follow a ballistic trajectory. These munitions have the disadvantage of requiring the addition of auxiliary devices to allow rearming of the weapon.
Breakup munitions, which fire a projectile comprising a steel- or tungsten-powder charge disposed in a brittle envelope, are also known. This type of projectile explodes under the influence of centrifugal inertia forces as it leaves the barrel. U.S. Pat. No. 3,338,167 and CH 445341 describe such munitions, which have the advantage of being firable without modifying the weapon.
A breakup projectile, however, has several disadvantages. First, such a projectile is costly, because it requires the production of a metal-powder charge with specific mechanical characteristics. Second, this charge must be sufficiently dense and compact to ensure the mechanical integrity of the projectile, but it must nonetheless disperse easily upon exiting the weapon barrel. Third, the integrity of such a charge during storage is uncertain because the metal powders oxidize, resulting in detrimental changes in the behavior of the projectile both while it is in the barrel and upon its exit. Moreover, these projectiles frequently explode inside the barrel of the weapon, and thus cause it to deteriorate. Furthermore, the dense powder dispersed in the vicinity of the mouth of the weapon may damage the weapon optics system and even injure personnel.